The invention relates to a ceramic multilayer capacitor comprising a number of ceramic layers on the basis of a doped (Ba,Ca)[Ti,Zr]O.sub.3 as well as a number of electrode layers of Ni, the ceramic layers and the electrode layers being alternately stacked to form a multilayer structure which is provided with electric connections at two side faces, said electric connections being connected to a number of the electrode layers. The invention also relates to a ceramic material which can suitably be used in a ceramic multilayer capacitor. The invention further relates to a method of manufacturing a ceramic multilayer capacitor.
Ceramic multilayer capacitors of the type mentioned in the opening paragraph are known per se. They are described, inter alia, in U.S. Pat. No. 5,319,517. This patent discloses, more particularly, a multilayer capacitor whose ceramic layers are made predominantly of a material which is based on doped (Ba,Ca,Sr)[Ti,Zr]O.sub.3. This material has a so-called perovskite structure. In the case of the known material, specific quantities of Ca ions and Sr ions are substituted at the Ba sites (so-called A-sites) of the perovskite structure, and a specific quantity of Zr ions is substituted at the Ti sites (so-called B-sites). The electrode layers of the known capacitor consist predominantly of Ni. In the manufacture of the capacitor, dopants including the metals Mn, Y, V and W and/or compounds which convert to their oxides upon firing are added to a calcined and milled powder of (Ba,Ca,Sr)[Ti,Zr]O.sub.3. Sintering aids are also added in order to reduce the minimum sintering temperature of the ceramic material. A relatively low sintering temperature is necessary to preclude that the Ni of the electrode layers melts during the sintering process.
The known ceramic multilayer capacitor appears to have a disadvantage. It has been found that, in practice, the indicated composition does not lead to optimum properties of the capacitor. It has especially been shown that the ever increasing requirements in terms of life time of the capacitor cannot always be met by the known capacitors.